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The Carver Challenge

Yes, very interesting.

Keith, surely one of the 'take-aways' from this is that competently designed amplifiers can, and do, sound different. The point is that differences can be tweaked in/out to taste, and don't need to cost £000's.
 
Agreed, well measuring amps need not sound identical. Also what one perceives as good sound quality may not be shared by all.

I'd go as far to add that absolute measured fidelity may not be the most enjoyable reproduction, but we know this already.
 
Agreed, well measuring amps need not sound identical. Also what one perceives as good sound quality may not be shared by all.

I'd go as far to add that absolute measured fidelity may not be the most enjoyable reproduction, but we know this already.
Couldn't agree more; good measured behaviours are likely a necessary, if not sufficient condition to enjoying the result overall.
 
Interesting article. I wonder if a time will come where the kind of 'amp modelling' we are all used to in the pro audio world where you can use plug-ins to get an emulation of say a Fender Twin, Marshall stack, Vox AC30, Ampeg SVT etc come to hi-fi. These emulators never sound like a mic in front of the real thing, but they do sound bloody good. It would be fun to have a integrated amp or active speakers where you could dial up say a McIntosh 275, KSA100, NAP250, Sugden A21, Leak Stereo 20, Quad II or whatever well loved classic amp to taste. Some would suit some music, others different stuff. It would get even more interesting if you could dial up whole studio control rooms, e.g. Abbey Rd in the 60s or 70s, RVG's Hackensack in the '50s and 60s, AIR, Sarm, Compass Point, Strawberry, BBC or wherever.
 
Couldn't agree more; good measured behaviours are likely a necessary, if not sufficient condition to enjoying the result overall.

Much depends where you set the aims and the goalposts IMO.

With 'quality' audio electronics you have good, good enough and perfect.

Taking amplifiers, 'good' amplifiers will display enough technical competence to sound enjoyable even though they audibly change the signal passing through. The differences should be audible in comparisons across a range of systems and to a wide range of ears. However, when compared to the differences between 'speakers, or the impact of room acoustics, even the difference between disparate designs like a Quad II and Audiolab 8000P is tiny into an easy-ish load ;) **

Then perhaps the largest group - good enough - means that most people, most of the time cannot detect the difference between one design and another. The technical performance may not be SOTA but, noise, FR, distortion and stability make them interchangeable in most systems. To most ears these will be considered transparent amplifiers and once in the system, the contributions to sonic signature can be ignored.

Then we have perfect. Of course nothing is actually perfect since all amplifiers will be non linear to some degree, but in this category the designs comfortably exceed the specification needed for absolute transparency. Many amplifiers exist in this category and have done for a few decades. They don't necessarily sound different to the 'good enough' group, and aren't necessarily preferred to the 'good' group.

But there is no magic at play, ever.

I do believe you can teach yourself to read a bench test and identify into which category to place an amplifier.



** Some may recall the old Quad sponsored blind comparison of the Quad II, 303 and 405 into Yamaha NS1000. A test which concluded that all three were indistinguishable. A surprise to many for sure.
However, the devil is in the detail. I believe the listeners failed to detect differences because the magnitude of the differences was too small for reliable detection using the chosen programme and 'speakers at the chosen power levels. For example, a reflex loaded 'speaker system with extended LF response would have placed more emphasis on the difference between the transformer, capacitor, and direct coupling of the three amplifiers. As would a 4 Ohm loading <50 Hz.....
In the event Quad elected to use a reasonably sensitive sealed box design, not too reactive and with good inherent mechanical LF damping.
The primary cause for expected differences between the amplifiers was therefore somewhat lessened. Naughty Quad.
 
** Some may recall the old Quad sponsored blind comparison of the Quad II, 303 and 405 into Yamaha NS1000.
A test which concluded that all three were indistinguishable. A surprise to many for sure.
However, the devil is in the detail. I believe the listeners failed to detect differences because the magnitude of
the differences was too small for reliable detection using the chosen programme and 'speakers at the chosen
power levels. For example, a reflex loaded 'speaker system with extended LF response would have placed more
emphasis on the difference between the transformer, capacitor, and direct coupling of the three amplifiers.
As would a 4 Ohm loading <50 Hz.....
In the event Quad elected to use a reasonably sensitive sealed box design, not too reactive and with good inherent mechanical LF damping.
The primary cause for expected differences between the amplifiers was therefore somewhat lessened. Naughty Quad.

Did anyone visiting the Quad demos of the 70s/80s, notice that they never played anythng too demanding of dynamics -
maybe a solo piano or at most, a quartet. In any event, coupling any power amp to the 44 pre-amp, which 'pre-strangled' the
programme, made them all sound the same.

As you say, naughty Quad.
 
Has anyone a link to that test? I'm curious as to it being "Quad sponsored" yet not using ESLs. I guess the 44 preamp, having adjustable output, was actually a requirement as little else could cope with the huge difference in sensitivity between the IIs and 303/405 (over a Volt difference IIRC).

PS I'd actually challenge the dynamic thing; Quad always used classical, which is far more challenging dynamically than typical rock or pop music (flat-earth small speaker 'fist punch' counts for nothing here!). There is absolutely nowhere to hide with solo piano and very few sysems can do it.
 
I have a vague recollection that the loudspeaker choice was suggested or agreed with some of the journalists at the time. As you suggest - why else would they not have used ESLs? I suspect that at that time, Quad was one of the more honest manufacturers.
 


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